This invention relates to a case, and more specifically to a case for holding a magnetic recording medium or other similar object.
Customarily a magnetic recording medium or the like is transported or stored as contained in a case. The case for such purpose usually is made of cardboard or plastics. For example, a plastic case 1 illustrated in FIGS. 10 to 14, for holding a cassette tape, comprises a cover 3 and a case body 5. The body 5 has ribs 9 for supporting the cassette tape 7 contained and lugs 11 for positioning the cassette, both formed inside in one piece with the body walls. The ribs and other protrusions are generally provided with some clearances between themselves and the cassette tape in the case. In a running automobile or other environment that involves vibration, the case tends to rattle as the clearances permit the cassette tape to strike against the inner walls of the case. This noise can be compounded by rattling of cases themselves where two or more such cases hit together. There is another possibility of the tapes scuffing or scratching each other, at a loss of the product quality. When the outer surface of a cassette and the inner surface of the case are caused to rub against each other, scuffing or scratching produces powder from the two parts. The powder in turn can deposit on the tape surface, increasing the dropout during playback. Moreover, their generally low coefficients of friction causes such plastic cases to slip out of the hand of the user, often to be broken.